1. Field of the Invention
Aspects of the present disclosure may relate to door closers for automatic closing of doors, and in particular may relate to door closers with a latch boost feature and that may be regenerative.
2. Description of Related Art
Door closers are used to automatically close doors, hold doors open for short intervals, and control opening/closing speeds in order to facilitate passage through a doorway and to help ensure that doors are not inadvertently left open. A door closer is often attached to the top or bottom of a door, and when the door is opened and released, the door closer generates a mechanical force that causes the door to automatically close without any user input. Thus, a user may open a door and pass through its doorway without manually closing the door.
Many conventional door closers are designed such that when opened a spring is compressed and energy is stored in the spring. When the door is allowed to close the energy stored in the spring is used to return the door to the closed position. Many different arm configurations exist for creating a desired force curve in the opened and closed direction. However all configurations have less force available in the closing direction than was required to open the door due to mechanical losses of the system. Additionally most configurations have the same shape curve in the opening and closing direction. Because, more force is desired in the latch region during close to overcome the latching hardware, most configurations require significant force to begin opening the door. Additionally the force must be set high enough to close the door under adverse conditions, such as stack pressure, leading to even higher forces required to open the door at times when the adverse conditions are not present.
Many conventional door closers are mechanically actuated and have a plurality of valves and springs for controlling the varying amounts of force applied to the door as a function of door angle and/or speed, as described above. A typical door closer may also have function of door angle and/or speed, as described above. A typical door closer may also have a piston that moves through a reservoir filled with a hydraulic fluid, such as oil. Adjusting the valve settings in such a conventional door closer can be difficult and problematic since closing times can vary because of the systems dependency on temperature, pressure, wear, and installation configuration. Moreover, adjusting the valve settings in order to achieve a desired closing profile for a door can be burdensome for at least some users. Many door closers exhibit much less than ideal closing characteristics because users are either unwilling or unable to adjust and re-adjust the valve settings in a desired manner or are unaware that the settings can and may need to be changed in order to effectuate a desired closing profile in the face of temperature changes, wear over time, and/or modifications to the physical installation.